Product accumulation systems are routinely used in conjunction with conveyors for the storage and accumulation of products which are fed from an upstream source onto conveyors. In the normal operation of this type system, products are placed on a conveyor at the upstream location, for instance at one operational station, and then transported to a downstream location by conveyor where the next step in the manufacture or distribution of the products is to be accomplished.
It is not uncommon that, during this process, there may be a disruption at a downstream location caused by a malfunction of machinery, some constraining problem like fallen or misaligned products, or other circumstance which prevents the downstream facility from accepting products. Continued operation of production upstream may result in the build-up of line back-pressure which could cause a further problem in permitting the unrestricted movement of products. However, if such a disruption is one which can be addressed relatively quickly, upstream products which normally would be transported to the malfunctioning location, can be received and temporarily stored by an accumulator which is integral to the system.
By employing such an accumulator, the upstream machinery can continue to operate by moving products to the accumulator. Since product movement can continue, there is no build-up of line pressure. Such a system also saves the substantial time and expense which would result in having to shutdown and then restart the entire system, if no accumulator was otherwise available.
As products are being received and retained by the accumulator, the downstream problem can be addressed. When that part of the system resumes full operation, the products stored in the accumulator are released to the downstream destination, with little downtime to the system. Products can also be received and stored at the accumulator in case there is an upstream disruption. In this case, accumulated products could be retained and sent downstream in order to keep the system operational while the upstream problem is being remedied.
The limitations and disadvantages of prior accumulator systems have been substantially overcome by the systems in U.S. Pat. Nos. 6,575,287 and 6,612,425. These systems disclose continuous single path conveyors, uniquely configured to transport products and comprising accumulator sections to accommodate and handle excessive product loads. However, these systems, as effective as they are, do not address special problems inherent in certain products or containers with particular shapes, sizes, configurations, or weights which make their movement and downstream feed more difficult. The specialized characteristics of such products containers may result in there being displaced or misaligned during the conveying process. This often results in the misfeeding of the product downstream or a build-up of line back-pressure due to fallen containers, with a subsequent disruption in the system. For example, relatively small packaged products often must be fed single file, from the conveyor system to the downstream destination. Such products must be properly aligned as they leave the conveyor system. If one or more of the products are askew, product feed to the downstream discharge may be blocked, causing a build-up of line back-pressure. A similar problem results from the movement, for example, of empty plastic bottle containers which, if not properly aligned for downstream discharge, may tip over, due to their high centers of gravity, again causing a disruption in the system.
In both these and other cases, there must be a free flow and proper alignment of products as the products are accumulated and then recirculated. If this free flow is interrupted, the accumulation process will be compromised and the products will reach the “turbulence point”: that is the area in which accumulation of products will result in falling or misaligned products, blockage of the system, and build-up of line back pressure, causing a virtual stoppage of product movement. It is important that the system does not permit the products from reaching this turbulence point.
Prior conveyor systems have been developed to address this and similar problems. One such system uses an actual step or drop-off between an accumulator and conveyor or between conveyors, in which products physically drop down or are caused to fall from one conveying surface to another. This has the obvious disadvantage of products becoming misaligned or actually falling over. Of course such a result leads to further disruptions of the system's operation.